40 X 20 33,000 Gallons In Ground; built 1993; Sand filter; 0.5 HP Pentair pump 1 skimmer, 1 main drain, 2 returns, Vinyl Floor and walls. I chlorinate my pool using granular Chlorine once every 3 days. Dont measure any chemicals and I think most of my problems because of not taking proper care. My Goal is to change my signature on all aspects to improve my pool